The present invention relates to a communication system and a communication management method, and particularly relates to a communication system and a communication management method in which connection requests or boot requests from client computers to server computers are controlled to make communications between the client computers and the server computers.
In a communication system constituted by a plurality of server computers disposed and aggregated in a data center or the like, and a plurality of client computers to be connected to the server computers through networks, communications from the client computers to the server computers are concentrated in the network located at the aggregation point where the server computers are disposed.
Generally, the communication data volume required for processing of connection from a client computer to a server computer is larger than the communication data volume with which the client computer uses ordinary service of the server computer. In addition, when the client computer makes a connection request, the client computer has to boot the server computer if the server computer has not been booted yet. The communication data volume required for processing to boot the server computer is also larger than the communication data volume required for ordinary data communication. Accordingly, communication data volume larger than that in ordinary data communication arises in the network located at the aggregation point in a period of time when connection requests rush from a large number of client computers to server computers, for example, when business is started.
When connection requests rush from a large number of client computers to server computers as descried above, it is likely that there is generated communication data volume larger than the allowable bandwidth of the network at the aggregation point. Thus, it is likely that there occurs congestion.
As a background-art technique capable of preventing the aforementioned congestion from occurring, for example, there is known a technique disclosed in JP-A-2000-232483 or the like. According to this background-art technique, when communication data volume increases beyond a threshold value of the network capacity in a communication system through a network, a communication path is established between nodes so as to increase the network bandwidth.
As another background-art technique, for example, there is known a technique disclosed in JP-A-2004-139291 or the like. This background-art technique relates to a data communication relaying apparatus, which makes control, for example, to reject relay of a connection request from a client computer in accordance with the number of connections established between server computers and client computers, so as to prevent congestion from occurring.